Image input apparatus and image input method

ABSTRACT

The image input apparatus comprises the image pickup unit which optically scans a subject and successively acquires partial images of the subject. The relative change detection unit detects an amount of relative change in position or speed of the image pickup unit between a time when a previous partial image was taken and a time when a current partial image is being taken. The an overlapping amount calculating unit calculates an amount of overlap between the previous partial image and the current partial image based upon the amount of relative change in position or speed detected by the relative change detection unit. The image recording determination unit determines whether or not the current partial image is to be recorded based upon the amount of overlap calculated by the overlapping amount calculating unit.

FIELD OF THE INVENTION

[0001] The present invention relates to image input apparatuses such asdigital cameras or non contact type handy scanners and image inputmethod. More particularly, this invention relates to the image inputapparatus and image input method which can pick up partial images atsuch timing that the amount of overlap among the partial images isproperly, and then composes the partial images into one image.

BACKGROUND OF THE INVENTION

[0002] Recently, in the portable information terminals, there have beenever increasing demands for inputting various documents, especially inthe mobile computer environments. These documents vary in a wide rangeincluding A 4 size to those sizes wider than this. In an attempt toachieve these demands, conventional flat bed scanners have problems inwhich it is difficult to carry these and it is also impossible to inputthe paper face of a document having a large size. In order to solvethese problems, for example, Japanese Patent Application Laid-Open No.11-73494 has proposed the following method. In this method, a scanningprocess is carried out with the input apparatus made in contact with thedocument, and the document image is acquired as a plurality of partialimages so that these are composed later to reproduce the document image.However, the action (operation) for carrying out the scanning with theapparatus made in contact with the paper face is inferior inoperability, resulting in a problem of a long input time.

[0003] Recently digital cameras are utilized as portable type scanners.Such a technique has been disclosed by, for example, Japanese PatentApplication Laid-Open No. 11-98485. In this method, an input apparatusis placed on the document side, and the input apparatus is allowed topick up an image of the document, and a distortion due to the imagepickup operation, in particular, in a diagonal direction is eliminated.However, problems with this image input apparatus disclosed by thisPatent Publication are that the resolution in the input image tends tobecome insufficient as a whole and that the resolution tends to varydepending on portions thereof located in front the input apparatus andthose portions located apart from the input apparatus.

[0004] Along with the development of digital image pickup apparatuseswith high resolution, the number of pixels in a CCD image pickup elementhas been remarkably improved; however, these are still insufficient inpicking up fine characters and patterns with good reproducibility.Therefore, a process has been proposed in which each portion of an imagepickup subject is picked up as a partial image, and these partial imagesare composed so that an image that looks as if it were taken by using animage pickup element having pixels with high density, with a wide angle.When an image with high precision is generated by using this composingtechnique of these partial images, the following points need to be takeninto consideration.

[0005] More specifically, each of the partial images requires anoverlapping area with respect to the adjacent partial image. Thecomposing process for the respective partial images is carried out basedupon image information on this overlapping area. In general, the greaterthe overlapping area, the higher the precision in the image composingprocess. However, on the other hand, there is an increase in the numberof partial images to be picked up, and consequently, an increasedprocessing time in the image composing process.

[0006] In this manner, when these partial images are picked up, it isnecessary to pick up images so as to maintain overlapping areas with aproper number of images. However, such an operation imposes considerableskills and errors on the photographer's side. In order to solve theseproblems, for example, Japanese Patent Application Laid-Open No.7-107379 has proposed “a still image pickup apparatus”. In Figures,reference number 1 represents an image pickup section for picking up animage from each portion of an image pickup subject, and for successivelyoutputting the resulting image data, reference number 2 represents apickup position orientation measuring section for measuring the positionand orientation of the image pickup section 1, and for outputtingposition orientation information, reference number 3 represents an imageselection section for finding the range of each image to be picked up onthe image pickup subject based upon the image data and the image pickuprange information successively sent from the image pickup section 1 aswell as based upon the position orientation information sent from thepickup position orientation measuring section 2, and reference number 4is an inner memory in which image previously picked up are stored.

[0007] In this still image pickup apparatus, the input apparatus is heldby the hand on a document, and the image pickup face is mechanicallyshifted so that, at each position, each partial image is automaticallypicked up by the image pickup face in a manner so as to have overlappingareas. However, it is not possible to input the paper face of large sizepaper, and it is necessary to take into consideration influences fromthe hand shaking, with the result that the overlapping areas are takenin an excessive manner.

[0008] Japanese Patent Application Laid-Open No. 9-261520 discloses animage input apparatus which can pick up a partial image with a properamount of overlap being maintained, while a scanning process is carriedout over a document by the hand in a non contact manner. As illustratedin FIG. 20, in this arrangement, the position orientation of the inputapparatus (pickup section 1) is measured, and based upon measuringinformation related to the position orientation, the current imagepickup range on the document is calculated, and based upon the resultsof the calculations, the amount of overlap over the previously picked upimage is estimated so that it is possible to carry out an imageacquiring operation at the time when an appropriate amount of overlaphas been obtained during the scanning process. Moreover, in this case,the size of the overlapping area is determined depending on the patternmatching (mutual correlation) between the two images in the inputimages.

[0009] However, the problem with the above mentioned conventional imageinput apparatus as described in Japanese Patent Application Laid-OpenNo. 9-261520 is that the orientation angles and positions of the inputapparatus with 6 degrees of freedom with respect to a subject need to bedetected, with the result that the apparatus becomes bulky and expensivein order to carry out these detections, resulting in an expensiveapparatus; therefore, this method is not suitable for a practical use.

[0010] Moreover, the size of the overlapping area is determined by usingpattern matching from an input image; however, in order to achieve thisprocess, it is necessary to input image at high speeds, with the resultthat a very expensive image pickup element is required and the apparatusis limited in the usable environments.

SUMMARY OF THE INVENTION

[0011] It is an object of this invention to provide a small sized,inexpensive image input apparatus and image input method which candetect a change in picked up images between a partial image previouslypicked up and a current partial image by using a simple structure, andwhich can properly maintain the amount of overlap of the partial imagesrequired at the time of image composition.

[0012] The image input apparatus according to one aspect of the presentinvention comprises an image pickup unit which optically scans a subjectand thereby successively acquires plural images of the subject that arepartial images of the subject having overlapping portions, wherein theimage pickup unit obtains the partial images by moving in a plane thatis parallel to a plane of the subject and without touching the subject;a relative change detection unit which detects an amount of relativechange in position or speed of the image pickup unit between a time whena previous partial image was taken and a time when a current partialimage is being taken; an overlapping amount calculating unit whichcalculates an amount of overlap between the previous partial image andthe current partial image based upon the amount of relative change inposition or speed detected by the relative change detection unit; and animage recording determination unit which determines whether or not thecurrent partial image is to be recorded based upon the amount of overlapcalculated by the overlapping amount calculating unit.

[0013] The image input apparatus according to another aspect of thepresent invention comprises an image pickup unit which optically scans asubject and thereby successively acquires plural images of the subjectthat are partial images of the subject having overlapping portions,wherein the image pickup unit obtains the partial images by moving in aplane that is parallel to a plane of the subject and without touchingthe subject; an angle detection unit which detects a change in angle ofthe image pickup unit based upon rotation angular velocities around twoaxes that are virtually parallel with an optic axis of said image pickupunit and mutually perpendicular to each to other between a time when aprevious partial image was taken and a time when a current partial imageis being taken; an overlapping amount calculating unit which calculatesan amount of overlap between the previous partial image and the currentpartial image based upon the change in angles detected by the angledetection unit; and an image recording determination unit whichdetermines whether or not the current partial image is to be recordedbased upon the amount of overlap calculated by the overlapping amountcalculating unit.

[0014] The image input apparatus according to still another aspect ofthe present invention comprises an image pickup unit which opticallyscans a subject and thereby successively acquires plural images of thesubject that are partial images of the subject having overlappingportions, wherein the image pickup unit obtains the partial images bymoving in a plane that is parallel to a plane of the subject and withouttouching the subject; an orientation detection unit which detects anorientation of the image pickup unit based upon rotation angularvelocities around two axes that are virtually parallel with an opticaxis of said image pickup unit and mutually perpendicular to each toother between a time when a previous partial image was taken and a timewhen a current partial image is being taken; a relative change detectionunit which detects an amount of relative change in position or speed ofthe image pickup unit between a time when a previous partial image wastaken and a time when a current partial image is being taken; anoverlapping amount calculating unit which calculates an amount ofoverlap between the partial images taken at the previous input time andthe partial images taken at the current input time based upon the amountof relative change in position or speed detected by the relative changedetection unit and the orientation detected by the orientation detectionunit; and an image recording determination unit which determines whetheror not the current partial image is to be recorded based upon the amountof overlap calculated by the overlapping amount calculating unit.

[0015] The image input apparatus according to still another aspect ofthe present invention comprises an image pickup unit which opticallyscans a subject and thereby successively acquires plural images of thesubject that are partial images of the subject having overlappingportions, wherein the image pickup unit obtains the partial images bymoving in a plane that is parallel to a plane of the subject and withouttouching the subject; a plurality of line sensors each of which detectsan amount of shift of the image pickup unit in the horizontal directionand in the vertical direction; an overlapping amount calculating unitwhich determines an amount of shift from input waveforms of the linesensors between the previous partial image and the current partialimage, and calculates an amount of overlap between the previous partialimage and the current partial image based upon the amount of shift; andan image recording determination unit which determines whether or notthe current partial image is to be recorded based upon the amount ofoverlap calculated by the overlapping amount calculating unit.

[0016] The image input apparatus according to still another aspect ofthe present invention comprises a first image pickup unit whichoptically scans a subject and thereby acquires plural images of thesubject that are partial images of the subject, wherein said imagepickup unit obtains the partial images by moving in a plane that isparallel to a plane of the subject and without touching the subject; asecond image pickup unit which continuously picks up the image that isbeing scanned; an overlapping amount calculating unit which calculatesan amount of overlap between the partial images picked up by the firstimage pickup unit based upon the image picked up by the second imagepickup unit; and an image recording determination unit which determineswhether or not the current partial image is to be recorded based uponthe amount of overlap calculated by the overlapping amount calculatingunit.

[0017] The image input apparatus according to still another aspect ofthe present invention comprises an image pickup unit which opticallyscans a subject and thereby successively acquires plural images of thesubject that are partial images of the subject having overlappingportions, wherein the image pickup unit obtains the partial images bymoving in a plane that is parallel to a plane of the subject and withouttouching the subject; a timer which counts time that has elapsed timefrom when the previous partial image was acquired; and an imagerecording determination unit which determines whether or not the currentpartial image is to be recorded based on the time counted by the timer.

[0018] Other objects and features of this invention will become apparentfrom the following description with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a block diagram that shows a basic structure of an imageinput apparatus in accordance with an embodiment of the presentinvention;

[0020]FIG. 2 is a flow chart that shows operations and processes from animage pickup to a composing process;

[0021]FIG. 3 is an explanatory drawing that shows a state of an imagepickup operation by the image input apparatus;

[0022]FIG. 4A to FIG. 4D are explanatory drawings that show states of animage to be picked up;

[0023]FIG. 5 is a flow chart showing a sequence of composing processesof partial images in accordance with an embodiment of the presentinvention;

[0024]FIG. 6A and FIG. 6B are explanatory drawings that show an exampleof extracted points corresponding to featuring points of partial imagesP(1), P(2) and P(1);

[0025]FIG. 7A to FIG. 7C are explanatory drawings that show a sequenceof composing processes of the partial images;

[0026]FIG. 8 is a block diagram that shows a construction of an imageinput apparatus in accordance with a first embodiment of the presentinvention;

[0027]FIG. 9 is an explanatory drawing that shows an example ofdetection of an amount of overlap in the image input apparatus inaccordance with the first embodiment of the present invention;

[0028]FIG. 10 is a block diagram that shows a construction of an imageinput apparatus in accordance with a second embodiment of the presentinvention;

[0029]FIG. 11 is an explanatory drawing that shows an example ofdetection of an amount of overlap in the image input apparatus inaccordance with the second embodiment of the present invention;

[0030]FIG. 12 is a block diagram that shows a construction of an imageinput apparatus in accordance with a third embodiment of the presentinvention;

[0031]FIG. 13 is an explanatory drawing that shows an example ofdetection of an amount of overlap in the image input apparatus inaccordance with the third embodiment of the present invention;

[0032]FIG. 14, which relates to a fourth embodiment, is an explanatorydrawing that shows an example of detection of an amount of overlap inthe image input apparatus having a structure of FIG. 8, 10 or 12 towhich a distance measuring sensor is added;

[0033]FIG. 15 is a block diagram that shows a construction of an imageinput apparatus in accordance with the sixth embodiment of the presentinvention;

[0034]FIG. 16 is an explanatory drawing that shows a detection state atthe time t and the time t+Δt in a line sensor in accordance with thesixth embodiment of the present invention;

[0035]FIG. 17 is a block diagram that shows a construction of an imageinput apparatus in accordance with a seventh embodiment of the presentinvention;

[0036]FIG. 18 is an explanatory drawing that shows an example of anacquired image by a high speed area sensor in accordance with theseventh embodiment of the present invention;

[0037]FIG. 19 is a block diagram that shows a construction of an imageinput apparatus in accordance with a eighth embodiment of the presentinvention; and

[0038]FIG. 20 is a block diagram that shows a construction of aconventional image input apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Embodiments of an image input apparatus according to the presentinvention have been explained below with reference to the accompanyingdrawings. However, the present invention is not intended to be limitedby these embodiments.

[0040]FIG. 1 is a block diagram that shows a basic structure of an imageinput apparatus in accordance with the present embodiment. In thisFigure, reference number 10 represents a lens for taking a subject imageand for converging it on an image pickup element, reference number 11 isan image pickup element, constituted by CCDs, etc., for obtaining animage signal of the subject image that has been converged by the lens10, reference number 12 is an A/D converter for converting the imagesignal (analog value) sent from the image pickup element 11 to a digitalsignal, reference number 13 is an MPU for carrying out variouscorrecting operations and compressing operations on the image signalthat has been converted to a digital value by the A/D converter 12,reference number 14 is an image memory for storing the image that hasbeen processed by the MPU 13, reference number 15 represents a displayapparatus which is constituted by display panels made from LCD, andwhich displays images immediately before they are stored and images thathave been stored in the image memory 14, reference number 16 is anoperation section for carrying out an image pickup operation and forturning the power supply ON/OFF, and reference number 17 is a switchused for picking up an image. Here, in addition to the above mentionedconstituent elements, other elements, such as a focusing use distancemeasuring sensor, a setting mechanism for the zoom magnification andsetting mechanisms for various modes, may be installed.

[0041] Operation of the image input apparatus will be explained now.FIG. 2 is a flow chart that shows operations and processes from an imagepickup process to a composing process. FIG. 3 is an explanatory drawingthat shows a state in which the image pickup process is carried out bythe image input apparatus. FIG. 4A to FIG. 4D are explanatory drawingsthat show states of an image to be picked up.

[0042] First, as illustrated in FIG. 3, the operator holds the imageinput apparatus 21 with the hand, turns the switch 17 ON (step S11), andcarries out a non contact scanning operation over a subject 20 to beinputted as image information, such as a document, a paper face, and apanel, with the switch 17 being kept ON. During this scanning operation,partial images, which correspond to a plurality of images obtained bydividing the subject image in a predetermined synchronized timing, arepicked up (Step S12) Thereafter, the switch 17 is turned OFF (step S13),and a composing operation is carried out (step S14).

[0043] In other words, when, for example, images have been picked up inthe order of images shown in FIG. 4A to FIG. 4D during the image pickupoperation, these images are composed so that the entire image or arequired portion of the subject 20 is generated as a sheet of imagecovering a wide range with high precision in the same manner as thesubject 20. Here, this image composing process may be executed in theimage input apparatus 21 main body, or the partial images may betransferred to a computer, etc., and the process may be executed in thepersonal computer. Moreover, the operation method for the image pickupis not intended to be limited by the above embodiment; and, for example,without installing the switch 17, the image pickup operation may beautomatically started at the time when the scanning is started.

[0044] Next, an explanation will be given on the composing method of thepartial images. FIG. 5 is a flow chart that shows a sequence of thecomposing processes of the partial images in accordance with the presentembodiment of the invention. FIG. 6A and FIG. 6B are explanatorydrawings that show an example of extracting points that correspond tofeature points of the partial images P(1), P(2) and P(1).

[0045] Here, supposing that each partial image is represented by p(i)(i=1 to N), and that the total number of the partial images isrepresented by N. First, as illustrated in FIG. 6A, partial image P(1),i=1, is loaded (step S21), and featuring points are automaticallyextracted from partial image P(1) (step S22). At this time, supposingthat partial image P(1) is in a state as shown in FIG. 6A, it ispreferable to extract corner portions 60 to 66 as indicated by circledportions as the featuring points. The features of this type may beextracted by using a differential filter, etc.

[0046] Successively, partial image P(2), (i+1), adjacent to partialimage P(1), is loaded (step S23), and points corresponding to thefeaturing points P(1) are extracted (step S24). When this partial imageP(2) is represented by FIG. 6B, points 60′ to 66′ corresponding to thefeaturing points 60 to 66 are extracted. The corresponding pointextracting process of this type is carried out by finding correlatedvalues on P(2) within a smaller image area centered on each featuringpoint on P(1), and the area which makes the correlated values maximum isfound so that the center of the area is extracted as a correspondingpoint.

[0047] Successively, a projection conversion parameter, which will bedescribed later, is calculated (step S25), and P(1) and P(2) arecomposed to one sheet of image (step S26) based upon the featuringpoints and the corresponding points. The following description willdiscuss an example of the composing process of these two images.

[0048] Here, suppose that coordinates of a point on P(1) are representedby (x, y), and corresponding coordinates on P(2) are represented by (x′,y′). When the subject is a plane surface, such as a paper face and awall, or an object located far away, the following relationship (1)holds. $\begin{matrix}{{x = \frac{{{h0} \cdot x^{\prime}} + {{h1} \cdot y^{\prime}} + {h2}}{{{h6} \cdot x^{\prime}} + {{h7} \cdot y^{\prime}} + 1}}{x = \frac{{{h3} \cdot x^{\prime}} + {{h4} \cdot y^{\prime}} + {h5}}{{{h6} \cdot x^{\prime}} + {{h7} \cdot y^{\prime}} + 1}}} & (1)\end{matrix}$

[0049] Here, h0 to h7 in equation (1), which are referred to asprojection conversion parameters, are inherent constant values betweenthe two images. Therefore, when there are not less than four pairs of afeaturing point and a corresponding point, these projection conversionparameters are determined. In general, since an image contains noise,several tens of pairs are used, and the least square method is used tocalculate the projection conversion parameters.

[0050] After the projection conversion parameters have been calculatedin this manner, calculations are carried out by using the abovementioned equation (1) as to which positions on P(1) all the pixels onP(2) are arranged. Thus, P(1) and P(2) are combined into one sheet ofimage (this is newly referred to as P(1)). The above mentionedcalculating processes are repeatedly executed until all the partialimages have been composed to form one sheet of image. In other words, iis incremented one by one (step S27), and the same process is carriedout until i has reached N (see step S28).

[0051] In other words, in case of the partial images shown in FIG. 4A toFIG. 4D, as illustrated in FIG. 7A to FIG. 7C, four images aresuccessively generated, and one sheet of composite image is thengenerated so that it is possible to generate an image with highprecision that covers a wide range.

[0052] Next, referring to specific examples, an explanation will begiven of the operation and construction of a apparatus for pickingpartial images up in predetermined synchronized timing, in order tomaintain a proper amount of an overlapping area between the partialimages.

[0053]FIG. 8 is a block diagram that shows the construction of an imageinput apparatus in accordance with the first embodiment of the presentinvention. In this Figure, reference number 30 represents a relativeposition detection section for detecting relative positions between acertain period of time in the image input apparatus, reference number 31represents an overlapping amount calculation section for detecting theamount of overlap (overlapped area) between partial images from thedetected value of the relative position detection section 30, andreference number 32 represents an image recording determination sectionfor determining whether or not the current partial image is recordablebased upon the amount of overlap calculated by the overlapping amountcalculation section 31. Here, the other constituent elements are thesame as those shown in FIG. 1; therefore, the same reference numbers areused, and the description thereof is omitted.

[0054] The relative position detection section 30 is constituted by, forexample, an acceleration sensor for detecting accelerations orthogonalto each other in a direction virtually parallel to an image pickup faceand an integral circuit. With respect to the acceleration censor, forexample, an inexpensive, small size piezoelectric acceleration censor isused.

[0055] In this case, supposing that the time at which a partial imagewas picked up previously is t, the relative position detection section30 makes it possible to detect a relative position at the current timet+Δt from the time t. When the relative position is detected from thevalue of acceleration, integrations are carried out twice; however, anintegration constant (initial acceleration) is not determined. Here,since it is supposed that, upon starting an image pickup operation, theacceleration is zero, the calculations are carried out assuming that theintegration constant is zero.

[0056]FIG. 9 is an explanatory drawing that shows an example of thedetection of the amount of overlap in the image input apparatus inaccordance with the first embodiment of the present invention. In FIG.9, reference number 40 represents an image input apparatus including thefunctional elements shown in FIG. 8, and reference number 41 is asurface of a subject.

[0057] Suppose that the relative position of the image input apparatus40 is displaced by dx in the x direction. Moreover, suppose that theimage pickup face of the image input apparatus 40 and the face of thesubject 41 are in parallel with each other. Furthermore, suppose thatthe distance from the image input apparatus 40 to the face of thesubject 41 is l. It is preferable to set the distance l to the closestvalue at the time when the operator inputs the subject.

[0058] Supposing that the field angle of the image input apparatus 40 inthe x direction is 2×θx, the length px1 of an area in which partialimages overlap each other is represented by the following equation:

px1=21 tan θx−dx   (2)

[0059] In the same manner, in the y direction that is orthogonal to thex direction, and parallel to the face of an image, the length py1 of anarea in which partial images overlap each other is represented by thefollowing equation:

py1=21 tan θy−dy   (3)

[0060] Here, it is assumed that the relative displacement of the imageinput apparatus 40 in the y direction is dy, and that the field angle inthe y direction is 2×θx. The overlapping amount calculation section 31carries out calculations of px1 and py1.

[0061] Thereafter, px1 and py1, thus calculated, are compared withpredetermined threshold values tx and ty in the image recordingdetermination section 32. At this time, when the following inequality issatisfied, an image recording signal is transmitted to MPU 13, and animage pickup operation is carried out:

px1<tx or py1<ty

[0062] When an image has been picked up, based upon this position as areference, px1 and py1 are calculated so as to newly pick up the nextimage adjacent thereto, and a judgment is made as to whether or not theimage recording is operable. Additionally, the above mentionedoverlapping amount calculation section 31 and the image recordingdetermination section 32 may be realized by software in the MPU 13.

[0063] Therefore, in accordance with the first embodiment, the relativeposition detection section 30 detects at least a directional componentin parallel with the image pickup face of a relative position of theimage input apparatus; the overlapping amount calculation section 31calculates the amount of overlap of a partial image that is beingcurrently scanned and is to be inputted by the image input apparatuswith respect to at least one partial image that has been inputtedbefore, based upon orientation detection values and shifting velocities;and the image recording determination section 32 determines whether ornot the current partial image is recordable based upon the amount ofoverlap. Thus, in comparison with a conventional arrangement in whichpositional orientation detections of 6 degrees of freedom are carriedout on a subject, it is possible to obtain the amount of overlaprequired at the time of image composition by using a smaller,inexpensive arrangement.

[0064]FIG. 10 is a block diagram that shows the construction of an imageinput apparatus in accordance with the second embodiment of the presentinvention. In this Figure, reference number 50 represents an angledetection section for detecting a change in angles between a certainperiod of time in the image input apparatus, reference number 51represents an overlapping amount calculation section for detecting theamount of overlap (overlapped area) between partial images from thedetected value of the angle detection section 50, and reference number52 represents an image recording determination section for determiningwhether or not the current partial image is recordable based upon theamount of overlap calculated by the overlapping amount calculationsection 51. Here, the other constituent elements are the same as thoseshown in FIG. 1; therefore, the same reference numbers are used, and thedescription thereof is omitted.

[0065] The angle detection section 50 is constituted by, for example, agyro sensor for detecting rotation angular velocities around two axesthat are orthogonal to each other in a direction virtually parallel toan image pickup face and an integral circuit. With respect to the gyrosensor, for example, a piezoelectric vibration sensor, which detects amovement of an object based upon Coriolis force, converts vibration of aright triangle pole to a vibration torque equal to the number ofoscillations of a tuning fork, and obtains a rotation angular velocityas an amount of change in voltage, is used. When the change in angles isdetected from the angular velocities, an integration is carried outonce. Supposing that the time at which a partial image was picked uppreviously is t, the angle detection section 50 makes it possible todetect a change in angles at the current time t+Δt from the time t.

[0066] In addition to this, another arrangement may be used in which anabsolute angle is detected by using an acceleration sensor and amagnetic sensor so as to calculate the change in angles. With respect tothe magnetic sensor, elements, such as a semiconductor hole element, asemiconductor magnetic resistance element, a magnetic body magneticresistance element and a magnetic induction type magnetic sensor, may beused.

[0067]FIG. 11 is an explanatory drawing that shows an example of thedetection of the amount of overlap in the image input apparatus inaccordance with the second embodiment of the present invention. In thisFigure, reference number 70 represents an image input apparatus arrangedas illustrated in FIG. 10, and reference number 71 is a surface of asubject.

[0068] Here, suppose that the image input apparatus 70 has an angularchange by φy around the y axis. Moreover, it is supposed that the x axisand y axis are axes that are in parallel with the image pickup face, andare orthogonal to each other while passing through the optical center ofthe image input apparatus 70. Furthermore, suppose that the distancefrom the image input apparatus 70 to the face of the subject 71 is 1,and that, in relation to the position of the image input apparatus 70 atthe time t, a relative position thereof at the time t+Δt is representedby (ex, ey). It is preferable to set the distance 1 to the closest valueat the time when the operator inputs the subject, or (ex, ey) may be setto (0, 0).

[0069] Supposing that the field angle of the image input apparatus 70 inthe x direction is 2×θx, the length px2 in the x direction of an area inwhich partial images overlap each other is represented by the followingequation:

px2=1 tan θx+1 tan(θx+φy)−ex   (4)

[0070] In the same manner, the length py2 of an area in which partialimages overlap each other is represented by the following equation:

py2=1 tan θy+1 tan(θy+φx)−ey   (5)

[0071] Here, the field angle in the y direction of the image inputapparatus 70 is set to 2×θy. Calculations on these px2 and py2 arecarried out in the overlapping amount calculation section 51.

[0072] Thereafter, px2 and py2, thus calculated, are compared withpredetermined threshold values tx and ty in the image recordingdetermination section 52. At this time, when the following inequality issatisfied, an image recording signal is transmitted to MPU 13, and animage pickup operation is carried out:

Px2<tx or py2<ty

[0073] When an image has been picked up, based upon this position as areference, px2 and py2 are again calculated so as to newly pick up thenext image adjacent thereto, and a judgment is made as to whether or notthe image recording is operable. Additionally, the above mentionedoverlapping amount calculation section 51 and the image recordingdetermination section 52 may be realized by software in the MPU 13.Moreover, in this embodiment, it is assumed that the image pickup faceof the image input apparatus 70 and the face of the subject 71 are inparallel with each other at time t; however, it may be assumed that theyare in parallel with each other at the time when the initial partialimage P(1) is picked up, and a change in angles may be calculated.

[0074] Therefore, in accordance with the second embodiment, the angledetection section 50 detects at least components around the two axesthat are orthogonal to the light axis and are virtually orthogonal toeach other of the rotation angle of the image input apparatus 70; theoverlapping amount calculation section 51 calculates the amount ofoverlap of a partial image that is being currently scanned and is to beinputted by the image input apparatus 70 with respect to at least onepartial image that has been inputted before, based upon the angularvelocities; and the image recording determination section 52 determineswhether or not the current partial image is recordable based upon theamount of overlap. Thus, even in the case of a great rotation by theuser and in the service environments, it is possible for the image inputapparatus to obtain the amount of overlap required at the time of imagecomposition by using a smaller, inexpensive arrangement, as comparedwith a conventional apparatus.

[0075]FIG. 12 is a block diagram that shows the construction of an imageinput apparatus in accordance with the third embodiment of the presentinvention. In this Figure, reference number 80 represents an angledetection section for detecting a change in orientation angles between acertain period of time in the image input apparatus, reference number 81represents a relative position detection section for detecting arelative position of the image input apparatus between a certain periodof time, reference number 82 represents an overlapping amountcalculation section for detecting the amount of overlap (overlappedarea) between partial images from the detected value of the angledetection section 80 or the detected value of the relative positionaldetection section 81, and reference number 83 represents an imagerecording determination section for determining whether or not thecurrent partial image is recordable based upon the amount of overlapcalculated by the overlapping amount calculation section 82. Here, theother constituent elements are the same as those shown in FIG. 1;therefore, the same reference numbers are used, and the descriptionthereof is omitted.

[0076] The angle detection section 80 is constituted by, for example, agyro sensor for detecting rotation angular velocities around two axesthat are orthogonal to each other in a direction virtually parallel toan image pickup face, and an integral circuit. When the change in anglesis detected from the angular velocities, an integration is carried outonce. The relative position detection section 81 is constituted by, forexample, an acceleration sensor for detecting accelerations that areorthogonal to each other in a direction virtually parallel to the imagepickup face, and an integral circuit.

[0077] When the relative position is detected from the value ofacceleration, integrations are carried out twice; however, anintegration constant (initial acceleration) is not determined. Here,since it is supposed that, upon starting an image pickup operation, theacceleration is zero, the calculations are carried out assuming that theintegration constant is zero. Moreover, a gravity component is mixedinto the value of acceleration. However, supposing that the accelerationby the scanning upon starting an image pickup operation is 0, the valueof acceleration at this time is exerted by gravity.

[0078] Here, supposing that time 0 is the starting time of an imagepickup operation, the value of the acceleration sensor is represented bythe following expression:

[0079] Next, the value obtained by the acceleration sensor at the time tis represented by the following expression:

[0080] The angle detection section 80 makes it possible to detect achange in rotation angles at the time t in relation to the time 0.Supposing that this three axes rotation matrix is represented by R, thedirection of gravity at the time t is represented by the followingexpression:

[0081] Here, the acceleration component by the scanning at the time t isrepresented by the following expression:

[0082] Based upon the above mentioned expressions, supposing that thetime at which a partial image was picked up previously is t, therelative position and the change in angles at the current time t+Δt inrelation to the time t can be detected.

[0083]FIG. 13 is an explanatory drawing that shows an example of thedetection of the amount of overlap in the image input apparatus inaccordance with the third embodiment of the present invention. In thisFigure, reference number 90 represents an image input apparatus arrangedas illustrated in FIG. 12, and reference number 91 is a surface of asubject.

[0084] Suppose that the image input apparatus 90 has an angular changeby φy around the y axis. Moreover, suppose that the relative position ofthe image input apparatus 90 is represented by (dx, dy, dz). Here, it issupposed that the x axis and y axis are axes that are in parallel withthe image pickup face, and are orthogonal to each other while passingthrough the optical center of the image input apparatus 90. Moreover, itis supposed that at the time t, the image pickup face of the image inputapparatus 90 and the face of the subject 91 are in parallel with eachother at the time t. Furthermore, suppose that the distance from theimage input apparatus 90 to the face of the subject is 1. The distance 1is preferably set to the closest value at the time when the operatorinputs the subject.

[0085] Supposing that the field angle of the image input apparatus 90 inthe x direction is 2×θx, the length px3 in the x direction of an area inwhich partial images overlap each other is represented by equation (6):

px3=1 tan θx+1 tan(θx+φy)−dx   (6)

[0086] In the same manner, the length py3 of an area in which partialimages overlap each other is represented by equation (7):

py3=1 tan θy+1 tan(θy+φx)−dy   (7)

[0087] Here, the field angle in the y direction of the image inputapparatus 90 is set to 2×θy. Calculations on these px3 and py3 arecarried out in the overlapping amount calculation section 82.Thereafter, px3 and py3, thus calculated, are compared withpredetermined threshold values tx and ty in the image recordingdetermination section 83. At this time, when the following in equalityis satisfied, an image recording signal is transmitted to MPU 13, and animage pickup operation is carried out:

px3<tx or py3<ty

[0088] When an image has been picked up, based upon this position as areference, px2 and py2 are again calculated so as to newly pick up thenext image adjacent thereto, and a judgment is made as to whether or notthe image recording is operable. Additionally, the above mentionedoverlapping amount calculation section 82 and the image recordingdetermination section 83 may be realized by software in the MPU 13.Moreover, in this embodiment, it is assumed that the image pickup faceof the image input apparatus 90 and the face of the subject 91 are inparallel with each other at time t; however, it may be assumed that theyare in parallel with each other at the time when the initial partialimage P(1) is picked up, and a change in angles may be calculated.

[0089] Therefore, in accordance with the third embodiment, the angledetection section 80 detects the orientation of the image inputapparatus, the relative position detection section 81 detects therelative position of the image input apparatus so that the overlappingamount calculation section 82 calculates the amount of overlap of apartial image that is being currently scanned and is to be inputted bythe image input apparatus with respect to at least one partial imagethat has been inputted before, based upon the orientation detection andthe shifting velocities, and the image recording determination section83 determines whether or not the current partial image is recordablebased upon the amount of overlap. Thus, it is possible to realize asmall size apparatus with higher reliability at low costs.

[0090] Fourth embodiment is a case in which, in any one of the abovementioned first to third embodiments, a distance measuring sensor formeasuring the distance from the subject in the light axis direction ofthe image input apparatus is installed. In other words, in thearrangement as shown in FIG. 8, FIG. 10 or FIG. 12, a distance measuringsensor is connected to the MPU 13. FIG. 14 is an explanatory drawingthat shows an example of the detection of the amount of overlap in animage input apparatus 100 in which a distance measuring sensor 101 isadded to the construction of FIG. 8, FIG. 10 or FIG. 12. In this Figure,reference number 100 represents the image input apparatus, referencenumber 101 is the distance measuring sensor, and reference number 102 isa surface of a subject.

[0091] With respect to the distance measuring sensor 101, any one of theultrasonic wave system, the optical system and the eddy current systemmay be used. For example, an active system which detects scattered lightof an infrared beam so that the distance is calculated by using thetriangulation may be used, or a passive system for measuring thedistance based upon the focal distance may be used. Alternatively, afunction used for auto focusing maybe used as the distance measuringsensor 101 in a combined manner.

[0092] As illustrated in FIG. 14, suppose that the image input apparatus100 is shifted from a position on the left to a position on the right.Suppose that distance information obtained by the distance measuringsensor 101 on the left position is represented by 11, and that distanceinformation obtained by the distance measuring sensor 101 on the rightposition is represented by 12. In this case, px1, py1, described in thefirst embodiment, are represented by the following equation (8):

px1=(l1+l2) tan θx−dx   (8)

py1=(l1+l2) tan θy−dy

[0093] Moreover, px2, py2, described in the second embodiment arerepresented by the following equation (9):

px2=l1 tan θx+l2 sin(θx+φy)−ex   (9)

py2=l1 tan θy+l2 sin(θy+φx)−ey

[0094] Furthermore, px3, py3, described in the second embodiment, arerepresented by the following equation (10):

px3=l1 tan θx+l2 sin(θx+φy)−dx   (10)

py3=l1 tan θy+l2 sin(θy+φx)−dy

[0095] Therefore, in accordance with the fourth embodiment, since thedistance measuring sensor 101 for detecting the distance from thesubject is installed in each of the image input apparatuses ofEmbodiments 1 to 3, the overlapping amount detection section is allowedto detect the amount of overlap between partial images by utilizing thedistance information from the distance measuring sensor 101; therefore,it becomes possible to maintain an overlapping area required upon imagecomposition more accurately.

[0096] Fifth embodiment is a case in which, in any one of the abovementioned first to fourth embodiments, an inclination of a subject isdetected, and this is utilized for the calculations on the amount ofoverlap. When the inclination of the subject is detected, distancemeasuring sensors, which measure distances to the subject in at leastthree directions that are not parallel to each other from the imageinput apparatus (in FIG. 14, distance measuring sensors 101 are placedin three directions that are not parallel to each other), are installed.In this case, when the distances at least in the three directions arefound, normal vectors (a, b, c) of the face of the subject with respectto the image input apparatus can be calculated.

[0097] Supposing that axes that are orthogonal to each other in parallelwith the face of the subject are x axis and y axis, the inclination ofthe image input apparatus with respect to the subject, that is, therotation angles (φx, φy around the x axis and y axis, are found fromequation (11): $\begin{matrix}{{{\phi \quad x} = {\tan^{- 1}\frac{b}{\sqrt{a^{2} + c^{2}}}}}{{\phi \quad y} = {\tan^{- 1}\frac{a}{b}}}} & (11)\end{matrix}$

[0098] Based upon the above mentioned equations, equations (8) to (10)are respectively represented by equations (12) to (14):

px1=(l1+l2) tan(θx+φy)−dx

py1=(l1+^(l)2) tan(θy+φx)−dy   (12)

px2=l1 tan(θx+φy)+l2 sin(θx+φy+φy)−ex

py2=l1 tan(θy+φx)+l2 sin(θy+φx+φx)−ey   (13)

px3=l1 tan(θx+φy)+l2 sin(θx+φy+φy)−dx

py3=l1 tan(θy+φx)+l2 sin(θy+φx+φx)−dy   (14)

[0099] Therefore, in accordance with the fifth embodiment, since, inEmbodiments 1 to 3, the distance from the subject is detected so thatthe overlapping amount detection section calculates the amount ofoverlap by utilizing this distance, not only information of the positionorientation on the image input apparatus side, but also information ofthe orientation of the subject can be inputted; therefore, it becomespossible to maintain an overlapping area required upon image compositionmore accurately.

[0100]FIG. 15 is a block diagram that shows the construction of an imageinput apparatus in accordance with a sixth embodiment of the presentinvention. In this Figure, reference number 110 represents a line sensorthat measures the amount of shift of the subject in the verticaldirection, reference number 111 represents a line sensor that measuresthe amount of shift of the subject in the horizontal direction,reference number 112 is an overlapping amount calculation section forcalculating the amount of overlap between partial images from the outputvalues of the line sensors 110, 111, and reference number 113 is animage recording determination section for determining whether or not thecurrent partial image is recordable based upon the amount of overlapcalculated by the overlapping amount calculation section 112. Here, theother constituent elements are the same as those shown in FIG. 1;therefore, the same reference numbers are used, and the descriptionthereof is omitted.

[0101] In this manner, the line sensor 110 and the line sensor 111 areplaced in a manner so as to be virtually orthogonal to each other. FIG.16 is an explanatory drawing that explains the output relationship ofthe line sensors at the time t and the time t+Δt. Based upon inputwaveforms of the line sensors 110, 111 at the time t in which a partialimage was picked up previously and input waveforms at the current timet+Δt, the overlapping amount calculation section 112 calculates theamount of shift of the partial image. Here, the respective amounts ofshifts of the line sensors 110, 111 are represented by px, py. Theamounts of shifts are compared with predetermined threshold values tx,ty in the image recording determination section 113.

[0102] When the results of the comparison in the image recordingdetermination section 113 satisfy the following inequality, an imagerecording signal is transmitted to MPU 13, and an image pickup operationof a partial image is carried out:

px<tx or py<ty

[0103] When the partial image has been picked up, based upon therespective values of the line sensors 110, 111 at this position as areference, px and py are again calculated by the overlapping amountcalculation section 112 so as to newly pick up the next partial imageadjacent thereto, and a judgment is made by the image recordingdetermination section 113 as to whether or not the image recording isoperable. Additionally, the above mentioned overlapping amountcalculation section 112 and the image recording determination section113 may be realized by software in the MPU 13.

[0104] In this manner, the line sensors 110, 111 that are orthogonal toeach other are placed, and the amount of overlap of a partial image thatis being currently scanned and is to be inputted by the image inputapparatus with respect to at least one partial image that has beeninputted before is calculated from the amounts of shifts of the linesensors 110, 111, so as to determine whether or not the current partialimage is recordable; therefore, this arrangement makes it possible toeliminate the necessity of carrying out the detection of the orientationand the detection of shifting speed of the image input apparatus, whichare not stable in precision and reliability.

[0105]FIG. 17 is a block diagram that shows the construction of an imageinput apparatus in accordance with the seventh embodiment of the presentinvention. In this Figure, reference number 120 represents a high speedarea sensor that acquires an image virtually in the same area as theimage pickup element 11 at high speeds, reference number 121 representsan overlapping amount calculation section for calculating the amount ofoverlap of the partial image that has been acquired by the high speedarea sensor 120, and reference number 122 is an image recordingdetermination section for determining whether or not the current partialimage is recordable based upon the amount of overlap calculated by theoverlapping amount calculation section 121. Here, the other constituentelements are the same as those shown in FIG. 1; therefore, the samereference numbers are used, and the description thereof is omitted.

[0106] In the above mentioned arrangement, first, the high speed areasensor 120 inputs an image within virtually the same area as the imagepickup element 11. Then, the overlapping amount calculation section 121calculates the amount of overlap between the input image to the highspeed area sensor 120 at the time t when the partial image waspreviously acquired and an input image to the high speed area sensor 120at the current time t+Δt.

[0107] In the calculation method of the amount of overlap, a mutualcorrelation is found between the two images, and the size of theoverlapping area between the two is found based upon positions at whichthe maximum values have been reached. For example, as illustrated inFIG. 18, when the calculation makes a judgment that the acquired imageat the time t and the acquired image at the time t+Δt overlap eachother, px, py are found. Then, these values are compared withpredetermined threshold values tx, ty in the image recordingdetermination section 122.

[0108] When the results of the comparison in the image recordingdetermination section 122 satisfy the following inequality, an imagerecording signal is transmitted to MPU 13, and an image pickup operationof a partial image is carried out:

px<tx or py<ty

[0109] When the partial image has been picked up, based upon therespective values of the line sensors 110, 111 at this position as areference, px and py are again calculated by the overlapping amountcalculation section 121 so as to newly pick up the next partial imageadjacent thereto, and a judgment is made by the image recordingdetermination section 122 as to whether or not the image recording isoperable. Additionally, the above mentioned overlapping amountcalculation section 121 and the image recording determination section122 may be realized by software in the MPU 13.

[0110] In this manner, the high speed area sensor 120 that successivelyacquires an image being scanned is placed, and the amount of overlap ofa partial image that is being currently scanned and is to be inputted bythe image pickup element 11 of the image input apparatus with respect toat least one partial image that has been acquired by the high speed areasensor 120 so as to determine whether or not the current partial imageis recordable; therefore, this arrangement makes it possible toeliminate the necessity of carrying out the detection of the orientationand the detection of shifting speed of the image input apparatus, whichare not stable in precision and reliability. Moreover, the high speedarea sensor 120, used for detecting the amount of overlap, is installedin a separated manner from the image pickup element 11 used for pickingup divided images; thus, selective modes are achieved in which thenormal image pickup element 11 is used for picking up divided imagesrequiring high resolution, while, in contrast, the high speed areasensor 120 having high speeds although the number of pixels is small isused for acquiring images used for overlapping amount calculations thatrequire high speed reading. Therefore, it is possible to achieve anapparatus that is more inexpensive and has higher performances, ascompared with conventional apparatuses.

[0111]FIG. 19 is a block diagram that shows the construction of an imageinput apparatus in accordance with the eighth embodiment of the presentinvention. In this Figure, reference number 130 represents a timer thatcounts time from the image pickup time of the previous partial image,and reference number 131 is an image recording determination section fordetermining whether or not the current partial image is recordable basedupon the counted time by the timer 130. Here, the other constituentelements are the same as those shown in FIG. 1; therefore, the samereference numbers are used, and the description thereof is omitted.

[0112] In the above mentioned arrangement, first, the timer 130 counts aperiod of time that has elapsed from the input time at which theprevious partial image was acquired. Then, the counted time is comparedwith a predetermined threshold value in the image recordingdetermination section 131. As a result of the comparison, when thecounted time exceeds the predetermined threshold value, an imagerecording signal is transmitted to MPU 13, and an image pickup operationof a partial image is carried out. When the partial image has beenpicked up, the time counting is resumed after the timer 130 has beenreset, and a judgment is made as to whether or not the image recordingis operable. This operation may be added to any one of the image inputapparatuses described in the aforementioned Embodiments 1 to 7. In thiscase, even when the input condition of the partial image in each of theEmbodiments is not satisfied, the image acquiring may be carried out,when the counted time has exceeded the above mentioned threshold value.Here, the image recording determination section 131 may be realized bysoftware in the MPU 13.

[0113] In this manner, the timer 130 for counting a period of elapsedtime from the previous image input is installed, and when the elapsedtime by the timer 130 has exceeded a predetermined value, the currentpartial image is acquired; therefore, this arrangement makes it possibleto carry out input the partial image while maintaining the amount ofoverlap of the partial image so that it becomes possible to achieve asmall size apparatus at low costs.

[0114] As described above, according to one aspect of the presentinvention, in the image input apparatus, when an image pickup unit isshifted so as to scan, at least direction components in parallel withthe image pickup face are detected as relative positions before andafter the shift, the amount of overlap between a partial image that waspreviously picked up and the partial image currently picked up iscalculated by using the direction components, and when the result of thecalculation is smaller than a predetermined value, the current partialimage is recorded, while the amount of overlap is greater than the abovementioned value, it is not recorded. Therefore, it is possible to obtaina sufficient amount of overlap required at the time of imagecomposition, and in comparison with a conventional arrangement in whichpositional orientation detections of 6 degrees of freedom are carriedout on a subject, a simpler arrangement is achieved by detecting onlyinformation related to relative positions. As a result, it is possibleto provide a small size image input apparatus at low costs.

[0115] According to another aspect of the present invention, in theimage input apparatus, when an image pickup unit is shifted so as toscan, at least components around two axes that are virtually orthogonalto the light axis of the image pickup unit are detected as a change inangles after the shift, the amount of overlap between a partial imagethat was previously picked up and the partial image currently picked upis calculated by using the direction components, and when the result ofthe calculation is smaller than a predetermined value, the currentpartial image is recorded, while the amount of overlap is greater thanthe above mentioned value, it is not recorded. Therefore, even in thecase of a great rotation by the user and in the service environments, itis possible to obtain a sufficient amount of overlap required at thetime of image composition, and in comparison with a conventionalarrangement in which positional orientation detections of 6 degrees offreedom are carried out on a subject, a simpler arrangement is achievedby detecting information of rotation angle of the image pickup unit. Asa result, it is possible to provide a small size image input apparatusat low costs.

[0116] According to still another aspect of the present invention, inthe image input apparatus, when an image pickup unit is shifted so as toscan, information of a change in angles or a relative position after theshift is obtained, the amount of overlap between a partial image thatwas previously picked up and the partial image currently picked up iscalculated by using the direction components, and when the result of thecalculation is smaller than a predetermined value, the current partialimage is recorded, while the amount of overlap is greater than the abovementioned value, it is not recorded. Therefore, in the same manner asthe third aspect of the present invention, even in the case of a greatrotation by the user and in the service environments, it is possible toobtain a sufficient amount of overlap required at the time of imagecomposition, and in comparison with a conventional arrangement in whichpositional orientation detections of 6 degrees of freedom are carriedout on a subject, a simpler arrangement is achieved by detectinginformation of a change in angles or a relative position after theshift. As a result, it is possible to provide a small size image inputapparatus at low costs.

[0117] Furthermore, a distance detection unit using a distance measuringsensor detects the distance between the subject and the image pickupunit, and the resulting detected value is added to parameters forcalculating the amount of overlap in anyone of the first to thirdaspects of the present invention so that the amount of overlap of thepartial images is calculated. Therefore, with respect to the apparatusesof the first to third aspects of the present invention, it is possibleto obtain a sufficient amount of overlap required at the time of imagecomposition more accurately, and it is also possible to provide a smallsize image input apparatus at low costs.

[0118] Furthermore, an inclination of the surface of subject isdetected, and the resulting detected value is added to parameters forcalculating the amount of overlap in any one of the first to fourthaspects of the present invention so that the amount of overlap of thepartial images is calculated. Therefore, since the orientationinformation is also used, it becomes possible to obtain a sufficientamount of overlap required at the time of image composition moreaccurately, and it is also possible to provide a small size image inputapparatus at low costs.

[0119] According to still another aspect of the present invention, inthe image input apparatus, the amounts of shifts of the image pickupunit in the horizontal direction and the vertical direction are found byoutput values of line sensors placed at positions that are orthogonal toeach other. Therefore, it is possible to eliminate the necessity of theorientation detection and the shift detection of the above mentionedaspects, and also to accurately carry out the detections of itsorientation and position following the shift of the image pickup unit,from the viewpoint of precision and reliability.

[0120] According to still another aspect of the present invention, inthe image input apparatus, a second image pickup unit, for example, ahigh speed area sensor, is installed. Therefore, it is possible toeliminate the necessity of the orientation detection and the shiftdetection, which are unstable in precision and reliability. Moreover, animage sensor (second image pickup unit) for picking up images used forcalculating the amount of overlap is installed in a separate manner fromthe image sensor (first image pickup unit) for picking up partialimages. Therefore, it is possible to achieve an apparatus havingselectable modes at low costs, in which the first image pickup unit isused for images requiring high resolution while the second image pickupunit is used at the time of high speed image pickup processes.

[0121] Furthermore, a timer counts a period of elapsed time from theinput time of the previous partial image, and based upon the resultingvalue, the amount of overlap is calculated so that, even when therespective sensors fail to properly detect due to any problem such asnoise, the information from the counting unit can be used.

[0122] According to still another aspect of the present invention, inthe image input apparatus, a timer for counting a period of elapsed timefrom the input time of the previous partial image is installed without aspecific unit such as an orientation detection unit, etc., and partialimages are inputted while maintaining an amount of overlap in accordancewith the output value of the timer. Therefore, this arrangementeliminates the necessity of any specific detection unit, and makes itpossible to achieve a small size image input apparatus at low costs.

[0123] Furthermore, the image input apparatus stops to pick up an imagewhen the image input apparatus has an amount of shift not less than apredetermined amount of shift. Therefore, it is possible to avoidpicking up blurring images (unnecessary images) that tend to occur whenthe amount of shift is great.

[0124] The present document incorporates by reference the entirecontents of Japanese priority document, 2000-200198 filed in Japan onJun. 30, 2000.

[0125] Although the invention has been described with respect to aspecific embodiment for a complete and clear disclosure, the appendedclaims are not to be thus limited but are to be construed as embodyingall modifications and alternative constructions that may occur to oneskilled in the art which fairly fall within the basic teaching hereinset forth.

What is claimed is:
 1. An image input apparatus comprising: an imagepickup unit which optically scans a subject and thereby successivelyacquires plural images of the subject that are partial images of thesubject having overlapping portions, wherein said image pickup unitobtains the partial images by moving in a plane that is parallel to aplane of the subject and without touching the subject; a relative changedetection unit which detects an amount of relative change in position orspeed of said image pickup unit between a time when a previous partialimage was taken and a time when a current partial image is being taken;an overlapping amount calculating unit which calculates an amount ofoverlap between the previous partial image and the current partial imagebased upon the amount of relative change in position or speed detectedby said relative change detection unit; and an image recordingdetermination unit which determines whether or not the current partialimage is to be recorded based upon the amount of overlap calculated bysaid overlapping amount calculating unit.
 2. The image input apparatusaccording to claim 1, further comprising: a distance detection unitwhich detects a distance between the subject and said image pickup unit,wherein said overlapping amount detection unit calculate the amount ofoverlap between the partial images based an information including thedistance detected by said distance detection unit.
 3. The image inputapparatus according to claim 1, further comprising: an inclinationdetection unit which detects inclination of the subject, wherein saidoverlapping amount detection unit calculate the amount of overlapbetween the partial images based on an information including theinclination detected by said inclination detection unit.
 4. The imageinput apparatus according to claim 1, further comprising: a timer whichcounts time that has elapsed time from when the previous partial imagewas acquired, wherein said image recording determination unit determineswhether or not the current partial images can be recorded based on aninformation including the time counted by said timer.
 5. The image inputapparatus according to claim 1, wherein said image recordingdetermination unit stops acquiring the images when the amount of shiftof said image pickup unit is greater than a desired value.
 6. The imageinput apparatus according to claim 1, further comprising an imagecomposing unit which composes all or a portion of the partial images ofthe subject to obtain a single image.
 7. An image input apparatuscomprising: an image pickup unit which optically scans a subject andthereby successively acquires plural images of the subject that arepartial images of the subject having overlapping portions, wherein saidimage pickup unit obtains the partial images by moving in a plane thatis parallel to a plane of the subject and without touching the subject;an angle detection unit which detects a change in angle of the imagepickup unit based upon rotation angular velocities around two axes thatare virtually parallel with an optic axis of said image pickup unit andmutually perpendicular to each to other between a time when a previouspartial image was taken and a time when a current partial image is beingtaken; an overlapping amount calculating unit which calculates an amountof overlap between the previous partial image and the current partialimage based upon the change in angles detected by said angle detectionunit; and an image recording determination unit which determines whetheror not the current partial image is to be recorded based upon the amountof overlap calculated by said overlapping amount calculating unit. 8.The image input apparatus according to claim 7, further comprising: adistance detection unit which detects a distance between the subject andsaid image pickup unit, wherein said overlapping amount detection unitcalculate the amount of overlap between the partial images based aninformation including the distance detected by said distance detectionunit.
 9. The image input apparatus according to claim7, furthercomprising: an inclination detection unit which detects inclination ofthe subject, wherein said overlapping amount detection unit calculatethe amount of overlap between the partial images based on an informationincluding the inclination detected by said inclination detection unit.10. The image input apparatus according to claim 7, further comprising:a timer which counts time that has elapsed time from when the previouspartial image was acquired, wherein said image recording determinationunit determines whether or not the current partial images can berecorded based on an information including the time counted by saidtimer.
 11. The image input apparatus according to claim 7, wherein saidimage recording determination unit stops acquiring the images when theamount of shift of said image pickup unit is greater than a desiredvalue.
 12. The image input apparatus according to claim 7, furthercomprising an image composing unit which composes all or a portion ofthe partial images of the subject to obtain a single image.
 13. An imageinput apparatus comprising: an image pickup unit which optically scans asubject and thereby successively acquires plural images of the subjectthat are partial images of the subject having overlapping portions,wherein said image pickup unit obtains the partial images by moving in aplane that is parallel to a plane of the subject and without touchingthe subject; an orientation detection unit which detects an orientationof the image pickup unit based upon rotation angular velocities aroundtwo axes that are virtually parallel with an optic axis of said imagepickup unit and mutually perpendicular to each to other between a timewhen a previous partial image was taken and a time when a currentpartial image is being taken; a relative change detection unit whichdetects an amount of relative change in position or speed of the imagepickup unit between a time when a previous partial image was taken and atime when a current partial image is being taken; an overlapping amountcalculating unit which calculates an amount of overlap between thepartial images taken at the previous input time and the partial imagestaken at the current input time based upon the amount of relative changein position or speed detected by said relative change detection unit andthe orientation detected by the orientation detection unit; and an imagerecording determination unit which determines whether or not the currentpartial image is to be recorded based upon the amount of overlapcalculated by said overlapping amount calculating unit.
 14. The imageinput apparatus according to claim 13, further comprising: a distancedetection unit which detects a distance between the subject and saidimage pickup unit, wherein said overlapping amount detection unitcalculate the amount of overlap between the partial images based aninformation including the distance detected by said distance detectionunit.
 15. The image input apparatus according to claim 13, furthercomprising: an inclination detection unit which detects inclination ofthe subject, wherein said overlapping amount detection unit calculatethe amount of overlap between the partial images based on an informationincluding the inclination detected by said inclination detection unit.16. The image input apparatus according to claim 13, further comprising:a timer which counts time that has elapsed time from when the previouspartial image was acquired, wherein said image recording determinationunit determines whether or not the current partial images can berecorded based on an information including the time counted by saidtimer.
 17. The image input apparatus according to claim 13, wherein saidimage recording determination unit stops acquiring the images when theamount of shift of said image pickup unit is greater than a desiredvalue.
 18. The image input apparatus according to claim 13, furthercomprising an image composing unit which composes all or a portion ofthe partial images of the subject to obtain a single image.
 19. An imageinput apparatus comprising: an image pickup unit which optically scans asubject and thereby successively acquires plural images of the subjectthat are partial images of the subject having overlapping portions,wherein said image pickup unit obtains the partial images by moving in aplane that is parallel to a plane of the subject and without touchingthe subject; a plurality of line sensors each of which detects an amountof shift of said image pickup unit in the horizontal direction and inthe vertical direction; an overlapping amount calculating unit whichdetermines an amount of shift from input waveforms of the line sensorsbetween the previous partial image and the current partial image, andcalculates an amount of overlap between the previous partial image andthe current partial image based upon the amount of shift; and an imagerecording determination unit which determines whether or not the currentpartial image is to be recorded based upon the amount of overlapcalculated by said overlapping amount calculating unit.
 20. The imageinput apparatus according to claim 19, further comprising: a timer whichcounts time that has elapsed time from when the previous partial imagewas acquired, wherein said image recording determination unit determineswhether or not the current partial images can be recorded based on aninformation including the time counted by said timer.
 21. The imageinput apparatus according to claim 19, wherein said image recordingdetermination unit stops acquiring the images when the amount of shiftof said image pickup unit is greater than a desired value.
 22. The imageinput apparatus according to claim 19, further comprising an imagecomposing unit which composes all or a portion of the partial images ofthe subject to obtain a single image.
 23. An image input apparatuscomprising: a first image pickup unit which optically scans a subjectand thereby acquires plural images of the subject that are partialimages of the subject, wherein said image pickup unit obtains thepartial images by moving in a plane that is parallel to a plane of thesubject and without touching the subject; a second image pickup unitwhich continuously picks up the image that is being scanned; anoverlapping amount calculating unit which calculates an amount ofoverlap between the partial images picked up by said first image pickupunit based upon the image picked up by said second image pickup unit;and an image recording determination unit which determines whether ornot the current partial image is to be recorded based upon the amount ofoverlap calculated by the overlapping amount calculating unit.
 24. Theimage input apparatus according to claim 23, further comprising: a timerwhich counts time that has elapsed time from when the previous partialimage was acquired, wherein said image recording determination unitdetermines whether or not the current partial images can be recordedbased on an information including the time counted by said timer. 25.The image input apparatus according to claim 23, wherein said imagerecording determination unit stops acquiring the images when the amountof shift of said image pickup unit is greater than a desired value. 26.The image input apparatus according to claim 23, further comprising animage composing unit which composes all or a portion of the partialimages of the subject to obtain a single image.
 27. An image inputapparatus comprising: an image pickup unit which optically scans asubject and thereby successively acquires plural images of the subjectthat are partial images of the subject having overlapping portions,wherein said image pickup unit obtains the partial images by moving in aplane that is parallel to a plane of the subject and without touchingthe subject; a timer which counts time that has elapsed time from whenthe previous partial image was acquired; and an image recordingdetermination unit which determines whether or not the current partialimage is to be recorded based on the time counted by the timer.
 28. Theimage input apparatus according to claim 27, wherein said imagerecording determination unit determines that the current image is not tobe recorded when the amount of shift of said image pickup unit isgreater than a predetermine value.
 29. The image input apparatusaccording to claim 27, further comprising an image composing unit whichcomposes all or a portion of the partial images of the subject to obtaina single image.
 30. An image input method comprising: an image pickupstep for optically scanning a subject and thereby successively acquiresplural images of the subject that are partial images of the subjecthaving overlapping portions, wherein said image pickup step obtains thepartial images by moving in a plane that is parallel to a plane of thesubject and without touching the subject; a relative change detectionstep for detecting an amount of relative change in position or speed ofsaid image pickup step between a time when a previous partial image wastaken and a time when a current partial image is being taken; anoverlapping amount calculating step for calculating an amount of overlapbetween the previous partial image and the current partial image basedupon the amount of relative change in position or speed detected by saidrelative change detection step; and an image recording determinationstep for determining whether or not the current partial image is to berecorded based upon the amount of overlap calculated by said overlappingamount calculating step.
 31. An image input method comprising: an imagepickup step for optically scanning a subject and thereby successivelyacquires plural images of the subject that are partial images of thesubject having overlapping portions, wherein said image pickup stepobtains the partial images by moving in a plane that is parallel to aplane of the subject and without touching the subject; an angledetection step for detecting a change in angle of the image pickup stepbased upon rotation angular velocities around two axes that arevirtually parallel with an optic axis of said image pickup step andmutually perpendicular to each to other between a time when a previouspartial image was taken and a time when a current partial image is beingtaken; an overlapping amount calculating step for calculating an amountof overlap between the previous partial image and the current partialimage based upon the change in angles detected by said angle detectionstep; and an image recording determination step for determining whetheror not the current partial image is to be recorded based upon the amountof overlap calculated by said overlapping amount calculating step. 32.An image input method comprising: an image pickup step for opticallyscanning a subject and thereby successively acquires plural images ofthe subject that are partial images of the subject having overlappingportions, wherein said image pickup step obtains the partial images bymoving in a plane that is parallel to a plane of the subject and withouttouching the subject; an orientation detection step for detecting anorientation of the image pickup step based upon rotation angularvelocities around two axes that are virtually parallel with an opticaxis of said image pickup step and mutually perpendicular to each toother between a time when a previous partial image was taken and a timewhen a current partial image is being taken; a relative change detectionstep for detecting an amount of relative change in position or speed ofthe image pickup step between a time when a previous partial image wastaken and a time when a current partial image is being taken; anoverlapping amount calculating step for calculating an amount of overlapbetween the partial images taken at the previous input time and thepartial images taken at the current input time based upon the amount ofrelative change in position or speed detected by said relative changedetection step and the orientation detected by the orientation detectionstep; and an image recording determination step for determining whetheror not the current partial image is to be recorded based upon the amountof overlap calculated by said overlapping amount calculating step. 33.An image input method comprising: an image pickup step for opticallyscanning a subject and thereby successively acquires plural images ofthe subject that are partial images of the subject having overlappingportions, wherein said image pickup step obtains the partial images bymoving in a plane that is parallel to a plane of the subject and withouttouching the subject; a detecting step for detecting an amount of shiftof said image pickup step in the horizontal direction and in thevertical direction; an overlapping amount calculating step fordetermining an amount of shift from input waveforms of the line sensorsbetween the previous partial image and the current partial image, andcalculates an amount of overlap between the previous partial image andthe current partial image based upon the amount of shift; and an imagerecording determination step for determining whether or not the currentpartial image is to be recorded based upon the amount of overlapcalculated by said overlapping amount calculating step.
 34. An imageinput method comprising: a first image pickup step for opticallyscanning a subject and thereby acquires plural images of the subjectthat are partial images of the subject, wherein said image pickup stepobtains the partial images by moving in a plane that is parallel to aplane of the subject and without touching the subject; a second imagepickup step for continuously picking up the image that is being scanned;an overlapping amount calculating step for calculating an amount ofoverlap between the partial images picked up by said first image pickupstep based upon the image picked up by said second image pickup step;and an image recording determination step for determining is whether ornot the current partial image is to be recorded based upon the amount ofoverlap calculated by the overlapping amount calculating step.
 35. Animage input method comprising: an image pickup step for opticallyscanning a subject and thereby successively acquires plural images ofthe subject that are partial images of the subject having overlappingportions, wherein said image pickup step obtains the partial images bymoving in a plane that is parallel to a plane of the subject and withouttouching the subject; a counting step for counting time that has elapsedtime from when the previous partial image was acquired; and an imagerecording determination step for determining whether or not the currentpartial image is to be recorded based on the time counted by saidcounting step.